A controlled method is required for the removal and examination of irradiated pelletized samples from a cylindrical containment capsule (xe2x80x9ccapsule xe2x80x9d). Frequently, the samples are new materials, usually exotic ceramics, which require special handling. The samples are often irradiated in a shielded radioactive facility. During irradiation, the samples are stored in the capsule. Typical capsule configurations have four or more symmetrically spaced cylindrical holes on the same axis as the capsule main body. The samples are stored in the holes during irradiation. At removal, the samples must be removed in a controlled manner to ensure their integrity. Since programs and processes for fabricating irradiated pelletized samples are continually changing, fixtures for removal must be adaptable.
In the past, samples were not handled in a highly controlled manner. For example, the prior art consisted of a fixture that clamped the capsule and used threaded drive screws to push out the pelletized samples. The clamp was stationary and a capsule was removed in order to reposition for removal of sample from a different hole. There were no provisions to orient the drive screws evenly with each sample, nor were there means to capture the pelletized samples upon removal in a secure fashion. Furthermore there were no means to adjust the position of the containment capsule while clamped.
The present invention integrates v-blocks to assure alignment of the push out rods and to securely receive the irradiated samples upon removal. V-block liners are inserted into the channel of each of the v-blocks to ensure cleanliness and orientation. To provide adjustment to the positioning of the containment capsules with the v-blocks, the capsule clamp is mounted on a micrometer slide that provides manual in/out movement and in turn is mounted on a jack that provides manual up/down movement. To take up less space in the facility, the fixture is in three separate pieces and the inherent simplicity of the fixture allows for remote manipulators to operate the sample removal process. The combination of the fixture features provide a controlled and remotely operated manner to remove pelletized samples from cylindrical containment capsules.
The design of the present fixture provides a simple and controlled manner to remove irradiated pelletized samples from a cylindrical containment capsule (xe2x80x9ccapsule xe2x80x9d). Prior to sample removal, the capsule is securely held on the fixture. The fixture securely keeps the capsule horizontal using an adjustable hold down clamp. The clamp is on the middle of one of the three fixture sections and is mounted on a manual micrometer translation slide for in/out translation. The translation slide is mounted on a laboratory jack that allows up/down translation. There is enough movement in these two motions to successfully position any capsule hole into push out position without requiring the clamped capsule to be removed, repositioned and re-clamped.
The two end sections contain identical v-blocks; one to guide the drive out screw and rods or manual push out rods and the other to receive the samples as they are driven out of the capsule. There are end blocks on both v-blocks. The rod guide v-block is adjustable to move up to the capsule preventing samples from falling out of other holes. There is a tray under the sample receiving block to catch samples should samples fall out of the v-channel. Stainless steel liners fit into the v-channels on the v-blocks. These can be remotely removed, replaced, and cleansed to prevent cross contamination between capsules or samples.
There are two methods used to advance the push rods in the capsule holes; manually advanced push rods and drive screw advanced push rods. The manually advanced push rods are bent weld rods of various sizes that are grasped by remote manipulators and are used for push out samples that can be easily removed from the holes. The drive screw advanced push rods are used to remove samples that require some controlled force to be removed and consist of a tapered drive screw and stainless steel tubing. The tubing lengths interlock by pins that are fastened in one of each tube that insert into the unpinned end of any tube. The various lengths of tubing allow the use of a single length drive screw by selecting the appropriate tube length.
The novel features of this invention are the removable (cleaned or discarded) stainless steel v-block liners in the v-blocks to keep sample orientation and cleanliness, and also offer a platform to examine samples and rotate them safely. Additionally, the ability to orient the capsule with the v-blocks and the push out rods, allows for sample removal of each sample of a capsule in a secure and controlled manner without requiring the capsule to be removed and re-clamped. The fixture is designed to be easily used by remote manipulators to remove samples and can be disassembled to take up less space.